While playing the game I found a "bug". I'm not sure if I can replicate it again, but what happen was on the 7th level of the second area as I picked up a health point I touched one of the crystals and because I was on my last life I died. But instead of repeating the level I moved up on to the next level.
Thanks for the report! There must be a single frame where you can still collect a power up once you have started the death sequence. So the end of level was triggered but as you had one health restored it thinks you have completed the level. Should be an easy fix although quite rare to trigger it as well.